Ntopng: Predictable from Observable State
CVE-2026-38968 is a critical-severity predictable from observable state vulnerability in Ntopng from Ntop, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Ntopng versions: 6.6 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Ntopng you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
ntopng through 6.6 is vulnerable to Predictable Session Identifier which can lead to Session Hijacking. HTTP session identifiers in src/HTTPserver.cpp use weak time-seeded pseudo-randomness during session creation. As a result, fresh authenticated logins can receive deterministic or colliding session cookies under attacker-controlled timing.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Predictable from Observable State
A number or object is predictable based on observations that the attacker can make about the state of the system or network, such as time, process ID, etc.
How developers prevent this class of flaw
- Increase the entropy used to seed a PRNG.
- Use products or modules that conform to FIPS 140-2 to avoid obvious entropy problems. Consult FIPS 140-2 Annex C (Approved Random Number Generators).
- Use a PRNG that periodically re-seeds itself using input from high-quality sources, such as hardware devices with high entropy. However, do not re-seed too frequently, or else the entropy source might block.
More Predictable from Observable State vulnerabilities (CWE-341)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in Ntopng
- 8.8 High severity
- 8.8 High severity
- 8.1 High severity
- 8.8 High severity
- 7.1 High severity
- 7.1 High severity
Recent Predictable from Observable State vulnerabilities
- 7.5 High severity
- 8.6 High severity
- 8.1 High severity
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